Bowl type concrete mixer



Dec. 22, 1931. F. O'REILLY 1,837,287

BOWL TYPE CONCRETE MIXER Filed Nov 20, 1929 2 Sheets-Sheet l INVENTOR. Fzmjvc ls O'REILLY ATTORNEYS.

Dec. 22, 1931. F. OREILLY BOWL/TYPE CONCRETE MIXER Filed Nov 20, 1929 2 Sheets-Sheet 2 IN V EN TOR. FRANCIS 0 REILLY WaZaA/J A TTORNE YS.

Patented Dec. 22, 1931 FRANCIS OVREILLY, OF SAN FBANCZSCO, UALIFOBNTA BOWL TYPE CONCRETE MIXER Application filed November 20, 1329. Serial No. 403,426.

This invention relates to concrete mixers and especially to portable concrete mixers of the vertical bowl type mounted on a motor truck arranged for operation by the truck motor as shown in my copending patent application filed September 12, 1928 under Serial No. 305,340.

The objects of the present invention are to. provide improvements in this type of mixer whereby a better mix is obtained in a shorter time and the apparatus is simplified. In the drawings hereto annexed Fig. 1 is a longitudinal vertical section of my apparatus as mounted on the chassis frame of a motor truck, a portion onlyof the frame be ing shown. Fig. 2.is a plan. view of the apparatus.

The frame of the truck is indicated at 1 l and secured above it is a special supportmg 99 base comprising outer 2 and inner .3 circular frame members connected by a plurality of radial members 1 convergingupward in the center so asto hold the central ring 3 somewhat elevated in respect to the outer ring 2. Above this spider-like base is a vertically disposed bowl-likecylinder 5 open on top and provided with a flat bottom 6 with a central opening 7.

Secured to the underside or formed integrally with the bottom-ofthe bowl is a circular track 8 resting on a plurality of rollers 9 revolvably mounted in brackets 10 secured to the radial members 4;

The bowl is heldhcentralized for rotation on the rollers by means of a circular lip 11 revolving freely. within the inner circular base frame member 3, and it carries a driving ring gear 12 engaged by a. pinion 13 on a vertical shaft 1% so that upon rotation of the shaft the bowl may be revolved;

The lower end of shaft 14. is supported in a bearing 15 secured to base frame 2 and just above this bearing is a large bevel gear 16 seon a small shaft 18 in turn geared as by chain 19 or otherwise to a power shaft 20 extending from the power take-off (not shown) of the truck. Such power take-off portions of trucks have as is well known several changes of speed and direction including a cured to the shaft and engaged by a pinion 17 bottomas they rotate.

neutral position so that the extension power shaft operated thereby may be given'differwhile preserving the main feature of the drive in relation to the truck, and which is to keep the transmission elements well toward the forward. part of the truck soas to v preserve freedom underneath the truck for Y a discharge spout 22.

Spout 22has a flange 23 at its upper end revolvably engaged by a flange 24: on a stationary pipe section 25 which is fitted with a sliding gate 26 and in turnis swivelly connected at 27 with a flange 28around-thedischargeopening 7 so that the bowl may be r0- tated.

Gate 26 is shown of slightly tapering form so as to fit tightly when closed, and it is pro vided with an extending rod 29. threaded along its outer portion as at 30 and engaged by a threaded hand-wheel 31 the hub 32 off. which is held against longitudinal movement so in a fixed bearing 33 so that by revolving the hand-wheel the gate may be closed or opened.

. vTo mix the concrete materials during the revolutionof the bowl I provide a plurality rof vertically disposed revolving spirals or 5 screws .34, 35, 36. These screws are like screw conveyors but preferably are without central shaft or core so as to present as little 7 resistance to the revolving mass of materials as possible. The lower ends of the spiral lades lie quite close to the bottom of the bowl and are beveled at the extreme ends as indicated so as to lift the material fromthe The upper ends of the spirals are provided with central hubs 37 clamped to the lower ends of short vertical shafts 38 revolvably supported in bearings 39' spaced above and below a train of gears 40 secured to the shafts, the gear of spiral 34: being in mesh with a pinion 41 on vertical drive shaft 14 positioned below a bearing 42 supporting the upper end of the shaft.

Bearings 39 and 42 are all supported on a box-like arm 43 secured at its forward end to transverse frame member 44 bent downward at its ends to form upright portions 45, and the box-like arm is braced by transverse members 46 passing over a portion of the bowl and secured at their outer ends to frame posts 47.

Gears 40 are positioned within the hollow arm structure so as to be protected from dirt and may virtually run in grease if desired.

Since the train of spur gears 40 causes the intermediate spiral 35 to revolve in reverse direction from the other two, spiral 35 is of reverse pitch so that all three will screw the material upward to cause a constant lifting thereof as the bowl revolves. Spiral 34 is closeto the wall of the bowl and revolves in a direction so that its periphery adjacent the bowl wall goes in the same direction to thereby reduce resistance to the material coming toward it.

Spiral 36 is arranged to slightly overlap the center or vertical axis of the bowl to prevent the formation of a dead core of unmixed material in the center of the bowl.

After mixing the material by simultaneous revolving of the bowl and spiral lifting screws. the gate is opened and the bulk of the load discharged bv gravity, but to thoroughly empty the bowl I provide a curved scraper 48 which is lowered into the bowl after the bulk of the load has run out. This scraper is carried at the end of a curved arm 49 which slides freely in brackets 50 mounted on top of box arm 43. in a manner so that the scraper may be raised clear of the material to dotted position. 48 and so held by means of a hook 51 on the base frame engageable with a hole 52 in the curved arm 49, or dropped into the bowl to work its way down by gravity to the bottom.

The scraper blade 48 is slanted in a direction so that it will tend to dig in during the rotation of the bowl and is placed at an angle as shown in Fig. 2 so that it will guide all material along the bottom and force it to the central opening.

I prefer the scraper blade suspended from above in the manner described as its tendeney is to hug the bottom and not ride the material as is more the tendency with a vertically descending scraper.

By considering Fig. 2 it will be seen that when the scraper is elevated the entire rear half of the bowl is unobstructed so that a load of concrete materials may readily be deposited therein from an overhead bunker, and the upper bearings of the spiral being of the closed end type and gearing all within the box-like arm no injury to the working parts can take place.

In operation the bowl revolves slowly to bring all material to the screws while the screws raise the material from the bottom to the top with a fountain-like action so that in a brief space of time every bit of material has been thoroughly intermixed many times.

While I show three revolving screws extending in the bowl intercepting the path of rotating material it is manifest that more may be used in larger bowls or fewer in smaller bowls, but the arrangement shown with the one working in opposite direction to the others has been found to give the best results for the amount of equipment used, though it is manifestthe screws need not be in a straight line. i

I claim:

1. In a mixer of the character described, a bowl-like receptacle, means whereby the receptacle is revolved around a vertical axis, a lifting screw conveyor extending down into the bowl, means for simultaneously revolving the bowl and rotating the screw for lifting material in the bowl as the same is revolved, and a bottom scraper mounted for lowering and raising in the bowl. said scraper provided with a blade arranged to drag material toward a. central opening in the bottom of said bowl.

2. In a structure as specified in claim 1, said scraper provided with a curved arm extending over the top of the bowl, and means at the top of the bowl guiding said arm for lowering and raising the scraper.

3. In a mixer of the character described, a bowl-like receptacle, means whereby the receptacle is revolved around a vertical axis, a screw extending down into the bowl, means for simultaneously revolving the bowl and rotating the screw for lifting material in the bowl as the same is revolved, a bottom scraper, means for lowering and raising the scraper in the bowl, and means for holding the scraper adjacent the top of the bowl.

4. In a mixer of the character described, a bowl-like receptacle, means whereby the re ceptacle is revolved around a vertical axis, a screw extending down into the bowl, means for simultaneously revolving the bowl and rotating the screw for lifting material in the bowl as the same is revolved, and a bottom scraper mounted for lowering and raising in the bowl, said scraper hung from above and formed to dig in toward the bottom as the bowl is revolved.

FRANCIS OREILLY. 

